A whistleblower at Infosys has asked Securities and Exchange Board of India (Sebi) to reject last week's consent settlement offer by the company and instead sought an independent forensic investigation by the market regulator into the severance pay to former Chief Financial Officer Rajiv Bansal.

The anonymous shareholder, whose mail to Sebi was reviewed by Business Standard, has also blamed the Infosys board led by co-founder Nandan Nilekani for dismissing the allegations, which were made by him or her.

"It is a real mockery of justice. The impunity with which the board, both past and present, dismissed the allegations when they knew they were wrong is unprecedented and, just for this reason Sebi should dismiss this settlement overture and prosecute the management and board to set an example," wrote the whistleblower who claimed to be an Infosys employee.

The whistleblower drew parallel to allegations of fraud at National Stock Exchange (NSE), which was investigated by the Sebi-appointed panel and got a clean chit.

"The current (NSE) management filed for consent but Sebi is not accepting that and asking for the special investigation. Why Infosys case should be different from the NSE case? Why Sebi did not order a fully independent investigation including a forensic investigation and make people accountable?" the letter said.

Infosys spokesperson said the company has not seen the letter.

In February, the petition by the anonymous whistleblower to Sebi alleging that there were irregularities in the acquisition of Israeli technology firm Panaya by Infosys and the subsequent severance pay to Bansal triggered at least two independent investigations. Both gave a clean chit to former chief executive Vishal Sikka and the company.

However, Infosys founder N R Narayana Murthy, who had made his outrage public against the failure of Infosys in disclosing the severance pay to shareholders and regulators, wanted the report to be made public. Infosys declined saying that confidential details were there in the report.

Pressure from Murthy made Sikka quit the company in August that prompted the board led by chairman R Seshasayee engage in a public spat with Murthy. Seshasayee and two board members quit in the aftermath.

As investors fled Infosys over a failed three-year experiment with its first non-founder CEO and the subsequent uncertainty, several board members, investors and former employees reached out to a reluctant Nilekani to return to the company.

One of the commitments made by Nilekani, who returned as non executive chairman, was to look at the probe reports dispassionately and offer his views.

In October, he gave a clean chit to Sikka on the issue and declined to make the probe report public citing confidentiality reasons. On December 2, Infosys named Salil S Parekh, a former Capgemini executive as the next CEO.

It approached Sebi on Wednesday with a consent plea to settle allegations of disclosure lapses on the Bansal payout, which analysts and former Infosys employees said that it was admitting to guilt.

The latest salvo at Infosys comes at a time when two former board members T V Mohandas Pai and V Balakrishnan, have asked Infosys to apologise to founder Murthy and also sought the exit of board members who were part of the discourse. Balakrishnan told PTI that Ravi Venkatesan and Roopa Kudva, who are board members of Infosys should resign for the lapse.

She was responding to a query to her on the microblogging platform whether she would resign from Infosys board.

The whistleblower letter to Sebi said that future disclosures on any wrongdoing could potentially not be exposed if Infosys is let off the hook in this episode.

"This is the first time an internal whistleblower had took pain to unravel a fictitious payment to an ex-CFO and a suspicious acquisition with personal conflicts attributed to senior management. If this case is settled through the back door then no whistle blower in future will take the pain to expose such things," the letter said.